A major objective is to characterize reactions of vitamin A associated with light adaptation and dark adaptation in the retina and to determine the mechanisms by which these reactions are geared into the metabolism of the retina. Specific aspects under study are the participation of binding proteins for vitamin A derivatives in reactions of vitamin A derivatives. BIBLIOGRAPHIC REFERENCES: Futterman, S.: The cell cycle, diabetes and the retina. Invest. Ophthal. 14, 4-6 (1975). Futterman, S., Saari, J.C., and Swanson, D.: Retinol and retinoic acid-binding proteins in bovine retina: Aspects of binding specificity. Exp. Eye Res. (1976) in press.